The previous chapters have highlighted the current and future threats to agricultural systems across the world. It is clear that current practices and models of agricultural development that have been followed during the last 50 years are far from satisfactorily addressing the challenges of poverty reduction, food security, and environmental sustainability. A total of 975 million people, most living in rural areas, do not have the food security they deserve. Under pressure from agriculture, both soil and water are being harmed, erosion accelerated, salinization and sea water intrusion progressed, and groundwater depleted. In addition, the current model of intensive agriculture is associated with a high carbon and greenhouse gas footprint, while at the same time many agricultural systems highly vulnerable to the predicted impacts of climate change.

The situation, however, varies substantially from one region to another in response to a combination of biophysical and socio-economic factors: climate, soil, water, population, economic development, as well as national policies and global changes. 

In the framework of this global study, it is thus necessary to describe and analyse the world’s main agriculture production systems and the particular challenges they face. The problems discussed in this chapter include the growing competition for land and water, land and water degradation, and the expected impacts of climate change. They occur with varying incidence and severity in the different agricultural land and water use systems across the world, and the main systems at risk are discussed at the end of this chapter.